(Click here to go to Lutheran Insulter; you won't be disappointed, unless your name is Erasmus of Rotterdam).
You rush forward as an ass under the pelt of a lion. (From Against Latomus, pg. 159 of Luther's Works, Vol. 32).
Not even really sure of the context of the quote...I'll save that research question for a rainy day. Unless someone who reads this wants to give a quick summary; I'd be happy to see some comments about that. But the main thing that struck me was: "How prophetic!" Clearly, Luther had no way of ever knowing what would come centuries later from the tip of another pen, that of C.S. Lewis. And I am sure (although I would love to be proven wrong on this) that Lewis had no idea about this quote when he wrote the seventh and final chapter of the Chronicles of Narnia, The Last Battle, a story in which a certain ass, named Puzzle rushes forward covered with a lion's pelt at the request of the real ass, Shift the ape, all in an attempt to imitate Aslan and lead Narnians astray.
The entire story is quite a delight and I highly recommend it. The Last Battle is probably one of the most underrated and under appreciated of the seven books, even though it is full of stunning imagery, Revelation-style hope and consolation including one of my favorite lines in all of literature: "Further up and further in!", it's a comforting book precisely because it reminds us of and points us to the one Lion who really does covers an ass like you and me, covered in the blood of the Lamb...covered by his holy precious blood and his innocent suffering and death. For where fools rush in (like asses all of us) under the pelt of this Lion, we are not rushing forward in vain or in idiocy, but to the very life and blood of the Lion, the Lamb and our Lord, to whom Aslan really points. That is something Shift could only imitate, and poorly at that. Thankfully, in the end, even Puzzle was forgiven his "ass-ness" and so are we as Christ draws us further up and further in to the cross and through the stable door to the Emperor beyond the sea.